/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.buffer;

/**
 * Implementations are responsible to allocate buffers. Implementations of this interface are
 * expected to be thread-safe.
 */
public interface ByteBufAllocator {

  ByteBufAllocator DEFAULT = ByteBufUtil.DEFAULT_ALLOCATOR;

  /**
   * Allocate a {@link ByteBuf}. If it is a direct or heap buffer depends on the actual
   * implementation.
   */
  ByteBuf buffer();

  /**
   * Allocate a {@link ByteBuf} with the given initial capacity. If it is a direct or heap buffer
   * depends on the actual implementation.
   */
  ByteBuf buffer(int initialCapacity);

  /**
   * Allocate a {@link ByteBuf} with the given initial capacity and the given maximal capacity. If
   * it is a direct or heap buffer depends on the actual implementation.
   */
  ByteBuf buffer(int initialCapacity, int maxCapacity);

  /**
   * Allocate a {@link ByteBuf}, preferably a direct buffer which is suitable for I/O.
   */
  ByteBuf ioBuffer();

  /**
   * Allocate a {@link ByteBuf}, preferably a direct buffer which is suitable for I/O.
   */
  ByteBuf ioBuffer(int initialCapacity);

  /**
   * Allocate a {@link ByteBuf}, preferably a direct buffer which is suitable for I/O.
   */
  ByteBuf ioBuffer(int initialCapacity, int maxCapacity);

  /**
   * Allocate a heap {@link ByteBuf}.
   */
  ByteBuf heapBuffer();

  /**
   * Allocate a heap {@link ByteBuf} with the given initial capacity.
   */
  ByteBuf heapBuffer(int initialCapacity);

  /**
   * Allocate a heap {@link ByteBuf} with the given initial capacity and the given maximal
   * capacity.
   */
  ByteBuf heapBuffer(int initialCapacity, int maxCapacity);

  /**
   * Allocate a direct {@link ByteBuf}.
   */
  ByteBuf directBuffer();

  /**
   * Allocate a direct {@link ByteBuf} with the given initial capacity.
   */
  ByteBuf directBuffer(int initialCapacity);

  /**
   * Allocate a direct {@link ByteBuf} with the given initial capacity and the given maximal
   * capacity.
   */
  ByteBuf directBuffer(int initialCapacity, int maxCapacity);

  /**
   * Allocate a {@link CompositeByteBuf}. If it is a direct or heap buffer depends on the actual
   * implementation.
   */
  CompositeByteBuf compositeBuffer();

  /**
   * Allocate a {@link CompositeByteBuf} with the given maximum number of components that can be
   * stored in it. If it is a direct or heap buffer depends on the actual implementation.
   */
  CompositeByteBuf compositeBuffer(int maxNumComponents);

  /**
   * Allocate a heap {@link CompositeByteBuf}.
   */
  CompositeByteBuf compositeHeapBuffer();

  /**
   * Allocate a heap {@link CompositeByteBuf} with the given maximum number of components that can
   * be stored in it.
   */
  CompositeByteBuf compositeHeapBuffer(int maxNumComponents);

  /**
   * Allocate a direct {@link CompositeByteBuf}.
   */
  CompositeByteBuf compositeDirectBuffer();

  /**
   * Allocate a direct {@link CompositeByteBuf} with the given maximum number of components that can
   * be stored in it.
   */
  CompositeByteBuf compositeDirectBuffer(int maxNumComponents);

  /**
   * Returns {@code true} if direct {@link ByteBuf}'s are pooled
   */
  boolean isDirectBufferPooled();

  /**
   * Calculate the new capacity of a {@link ByteBuf} that is used when a {@link ByteBuf} needs to
   * expand by the {@code minNewCapacity} with {@code maxCapacity} as upper-bound.
   */
  int calculateNewCapacity(int minNewCapacity, int maxCapacity);
}
